Drill chip breaker



2 Sheets-Sheet 1 6 4 m w 4 5 m U Z a m, a, imw amw v ui vm k INVENTOR. Erik Hallden E. HALLDEN DRILL CHIP BREAKER dink, %%#-4*w Jul 11 '1950 Filed July 21, 1947 E. HALLDEN DRILL CHIP BREAKER July 11, 1950 2 Sheets-Sheet 2 Filed July 21, 1947 INVENTOR Enk Hallden UNITED- STATES OFFICE D ILL CH EAKERv Erik Hallden, Detroit, Mich., a-ssignor to Ex- Cell-: Corporation, Detroit, Mich., a corpora;-

tion Michigan;

Apglication-Iulx 21, 1947; SjerialN'o. 762,2681

Claims. (Cl. 772-3 3).?

The invention relates; todrill chip breakers generally, and more particularly-to an improved chip breaker of the type adapted; to beincorgorated in the rotarydrive for a drill; and oper ative alternately to, exertan axialthrust on the drill and relieve it' during its 'rotation' for the QHIDOSB. of severing previously formed chip curls.

One object of the invention is to provide a drill chip breaker, operative to effect-axial retraction andprojection oi' the: drill incident to the I rotation oi, the drill through a very smallangle and n a manner wh h ff tua y. e m a es any tendency to set up anyundesirable vibration in the supporting; structure of the; associated machine.

n th r obj isorrqvidea dr 1'1 h p breaker inwhichthe alternate axialgreliei and projection oilthe. tool is effected through the medium of antiiriction bearing means adapted to absorb-the ax-iall thrust imposed on the tool, and in: which he bear ng emen s re rang d i a o manner to insu e an adequa and ba nc thr st n the tool s cnqrti s m nt at all t mes v V A u r bject is to; provide a r l" hip breaker characterized by simplicity of constrnctoionisma siz 10w in rnal i ict QMI- IQ E FI and ability to functionei'ficiently for longperiods without. r quiring repai r acem t, f ar s- Other objectjsandadvantages of the invention will become apparent. from, the following, detailed de c pt on i th p efred embod ment lustrated. the, accompanying drawings, in which:

Figure 1 isa side view of, a drill chip. breaker embodying the features of; the invention.

F st 2 is a t p View of the chi breaker Rig. 3. isfia longitudinalsectional view of the chin breaker.

4 is av transverse sectional, View or the chic br ak r en in ori ont l p ne su stantially on'the line 4- 401 Fig, 3

Fig, 5is. a transversesectional View of the, chip breaker taken in. a horizontalplanesubstantially on the line 5+5of Fig, 3.

Fig, 6 isa transversevse tionalyiew of, the, chip breaker a n n ah izpntal ple esubsiami l r on e ine 6-li v0i h s, shqwi e t e relative positions. of. the

.c a s wh ih t pl; s rer cve v H s- 7v a sec i nal. i w sim lar tofirs io ins he rela ive pcsi ns th arts whe th ool; is pr jected.

Fi ,8 is, a fra menta y ec cnal v ew taken ina p e s bst nt al Q11 t e i e in F sho i g the" te m of ne i h drop gro ves;-

While the invention is susceptible of various modifications and alternative constructions, have shown in the drawings and will: herein describe in detail the preferred embodiment, but it is to be understood that I do not thereby intend to limit the invention to the specific form dis-i. closed; but intend to cover all-modifications and alternative constructions falling within the spirit and scopeof the invention as expressed in the appended claims.

Referring moreparticularly tothe drawings; the drill chip breaker selected to illustrate the invention cpmprisesacasing I0 (Figs. 1 and 3) having a hollow cylindrical body section II- with an inturned annularflange l2 at one end; A flanged cover section 13 is removably secured'to the other end of the body section, as; by screws I2 4. Extending through a central opening IS in the cover section I -3 is a rotary driving membet l6 adapted to be connected with and supported from a spindle l1 constituting the tool supporting.

element of a machine tool. The driving member I6 is maintained inassembl'ed relation with the casing It by a circumferential flange l8 formed thereon and engaging a recess: IS in the inner face of the cover member ['3 concentric withthe opening I 5; An arm 20 rigid with and projecting laterallyfrom thecover section I3 is adapted to hold the casing stationary when the driving member k6; is rotated.

Extendingthrough theopening defined bythe flange, I2" of the body section H; is a driven member 2| adapted to; support a rotary cutting tool; such as a drill 22, in. axial relation. The outer or praiecting end ofjthe, driven member 21 may be of any preferred construction, depending upon the, manner in which the tool 22 has to be supported. As herein shown, the member is formed with, a tapered socket 213 for receiving the complementally tapered shank of the tool 2-2: A transverse slot 24 at the base of the socket is provided for reception Of a diametrical tang 25 formed on the end of the tool shank, whereby the tool isjnonrotatably anchored to the driven b r The driv rifmembe 2' nedn assembled relationwith the casing Ill by an ral, ircumferent al f an e 26 d ed to e t. a a n t t nne fac o th f ng .v

h dr and dr e .v emb r .2 are alined axially and are interconnected within the casing l0 ior rotation as a unit and for limited relative axial movement. To this end one of-the members, in this instance the driven member 21 is formedwith a diametrical tang 3d having a cylindrical axial extension which serves as 3 a pilot for accurately alining the parts. The adjacent end of the companion or driving memher It is formed with an axial recess 3| complemental in cross section to the tang 3i! and adapted to receive the same with a sliding fit.

'A bore 3| extends axially inwardly from the recess to receive the pilot 30. Thus the driven member 2| is constrained to rotate with the driving member l5 and is free to shift axially rela tive thereto without interrupting the driving connection.

In accordance with the invention, antifrictio bearing means is provided within the casing If;

for transmitting the axial thrust of the driving member Hi to the casing H) and from the casing to the driven member 2| to feed the tool to the work. The antifriction bearing means is constructed and arranged so as to alternately project the driven member axially away from the driving member, and then to relieve the driven member to permit it to return to its initial position relative to the driving member as an inoident to the rotation of the members with respect to the casing ID. More particularly, the arrangement of the bearing means is such that as the tool is fed to the work by a uniform advance of the spindle II, the bearing means is effective during a major portion of each revolution of the tool to exert an outward thrust on the driving member 2|, causing the tool to advance with the spindle. In the succeeding portion of the revolution, the outward thrust on the driven member 2| is relieved to permit a momen tary dwell or slight retraction of the tool, followed by its immediate projection axially to its initial position relative to the driving member. These deviations of the drill 22 from uniform feeding advance are effective to sever the chip curls formed by the tool during the preceding portion of its revolution.

In the preferred embodiment of the invention, the bearing means comprises an annular hearing plate 35 disposed between the flanges l8 and 2B of thedriving and driven members and encircling the lower end of the driving member.

The bearing plate 35 is clamped between the body section II and cover section It of the casing and isnonrotatably secured thereto by the screws l4. The axial thrust of the driving member I5 is transmitted to the bearing plate 35 through a series of bearing elements, herein shown as balls 36 retained in a suitable cage 31 and adapted to coact with complemental annular bearing tracks 38 and 39 formed respectively in the lower face of the flange I8 and the upper face of the bearing plate 35.

Interposed between the upper face of the flange 26 on the driven member 2| and the lower face of the bearing plate 35 which are formed to provide opposed annular bearing tracks is an antifriction bearing unit comprising an annular cage or bearing retainer 4| having a series of circumferentially spaced pockets for the accom: modation of bearing elements 42, preferably ball bearings. In the exemplary embodiment of the invention, the cage is provided with six pockets for the accommodation of six of the bearing ele' ments, and these pockets are spaced apart in a particular manner, as explained hereinafter. The opposed faces of the flange 26 and bearing plate 35 form rotating and stationary tracks upon which the bearing elements 42 roll when the driven member is rotated, thus causing the cage 4| to progress at one half the rotative speed of the driven member 2|.

To effect the intermittent relief and projection of the driven member 2|, the bearing elements 42 are arranged in a predetermined pattern in the cage 4|, and the bearing face of the stationary plate 35 is formed with a, series of relatively shallow rounded drop grooves 43 arranged in a similar pattern so as to register with the bearing elements only when the bearing cage occupies certain definite positions with respect to the bearing plate. In all other positions of the bearing cage, a plurality of the bearing elements 42 engage the bearing surface of the plate 35 and the driven element is held in fixed relation to the driving element I6. As the cage 4| moves into any relief position, the bearing elements enter the grooves 43, and allow the driven member to retract. When this occurs during the advance of the spindle II, the feeding movement to the tool is interrupted or substantially decreased, thus introducing. momentary dwell in the cutting action of the same. In the continued rotation of the bearing cage 4|, the bear ing elements 42 climb out of the grooves 43, and project the driven member 2| axially away from the driving member l6 and into the normal operating position.

In the preferred form of the chip breaker, the bearing elements 42 and drop grooves 43 are arranged in a pattern such that the tool is relieved momentarily and projected once in each revolution of the tool. To effect these movements while the tool is turning through a relatively small angle, the grooves 43 are made relatively narrow, as for example, of a width corresponding approximately to the diameter of one of the cooperating bearing elements 42. The range of movement of the driven member is determined, of course, by the depth of the grooves 43 and may be relatively small movements on the order of .014 of an inch being satisfactory for the purpose. Such small but rapid movements of the driven member 2| enable the tool to effectually sever the chip curls formed in its operation and eliminate any tendency to set up undesirable vibratory'movement in the structure of the as sociated machine.

To provide a balanced thrust on the driven member 2|, six of the grooves 43 are provided, and these grooves are extended diametrically across the face of the bearing plate 35. The six bearing elements 42 carried by the cage 4| are arranged in pairs with the element of each pair disposed on opposite sides of the rotation-a1 axis of the cage 4| so that the bearings of each pair engage simultaneously with opposite ends of the same groove 43. The pairs of bearing elements and grooves are spaced apart non-uniformly so that the driven member is sustained by at least two bearing elements, and preferably by four elements, while the companion elements are passing over grooves between the relief positions.

A particularly satisfactory arrangement of the bearings 42 and grooves 43 is shown in Fig. 5, in which the grooves are spaced from one another at arcuate intervals of 40, 60 and 80, and the companion pairsof bearing elements 42 are similarly spaced apart in the cage 4|. With this arrangement, only when the bearing elements 42 and the grooved bearing plate 35 are alined symmetrically as shown in Fig. 6 can all of the bearing elements drop into the correspondingly spaced grooves and thereby momentarily relieve the axial thrust on the drill. Immediately preceding such relief, during relief and immediately following relief, all six of the bearing elements aria-me are '"sition to snarethe; thrust load? This number ismomentarily reduced to four whencne anthem all opposedi-pa'ir,orbearingelements-t2 passes ave groove other than thejon'e' which occupies the same angular position in the patterns the pair of elements passm over it. At sucli'tlines'the other four bearing elements are in engagement with the bearing surfaceof the plate 35 and are therefore eifective to support the tiiiiust load; h

It will be apparent from the foregoing that the invention provides a drill! chip breaker of novel and advantageous construction. Through a novefaffangement of antifl-ictionlbearings, the is momentarily relieved" and projected while being rotated through a relatively small angle, thus enabling it to effectually sever the chip curls formed by its action on the work and eliminating any tendency to set up undesirable vibration in the supporting structure with which it is associated. Moreover, the improved construction provides a balanced axial thrust on the drill supporting member at all times, thus reducing stresses on the drill and the work, and enabling the drill to function with a high degree of precision.

I claim as my invention:

1. A drill chip breaker comprising, in combination, a rotatable drill holding member, bearing means for imparting an axial feeding thrust on said holding member, said bearing means including means rigid with the holding member providing an annular axially facing bearing track, a fixed bearing member providing on one face an annular bearing track in opposed relation to said first mentioned bearing track, said bearing member having on said one face three relatively shallow drop grooves extending diametrically across the bearing track, said grooves being spaced apart respectively by arcuate intervals of 40, 60 and 80, a series of roller bearing elements interposed between said bearing tracks including two elements for each of said grooves arranged in pairs for cooperation with the grooves on opposite sides of the axis of the holding member, and a cage operative to retain the pairs of bearing elements spaced apart at arcuate intervals corresponding to the spacing of said grooves.

2. A drill chip breaker comprising, in combination, a rotatable drill holding member, bearing means for imparting an axial feeding thrust on said holding member, said bearing means including means rigid with, the holding member providing an annular axially facing bearing track, a fixed bearing member providing on one face an annular bearing track in opposed relation to said first mentioned bearing track, said bearing member having in said one face three relatively shallow drop grooves extending diametrically across the bearing track, said grooves being spaced from each other at predetermined arcuate intervals, a series of roller bearing elements interposed between said bearing tracks including sitforr asthat pair and all of? the bearing ele-- ments" register with" and. drop into theirasso' ciat'ed grooves only whenthe cage andsaid bear ing"rneniber-a1'e-- positioned to aline the grooves and bearing elements symmetrically.

3; A drill chip breaker comprising, iii-combination; rotatable drill holding member, bearing rhea for" iniparti'hg an axial feeding thrust on saie nemmg member, said 'bearingmeans including: means rigid 'with the holding member providing an annular axiallyfacing bearing'track; a hired member providing on one face an annular bearing track in" opposed relation to said first mentioned bearing track, said bearing member having-in saidone-xface a plurality of drop grooves extending dierrnetric'ally across the bearing" track and spaced from each other at predetermined unequal arcuate intervals, a plurality of bearing elements interposed between said bearing tracks including a pair for each of said grooves, means for maintainin said pairs of elements in the same spaced relation as said grooves while the elements progress around said bearing tracks incident to the rotation of said holding member, the spacing of said grooves and said bearing elements being such that all of the bearing elements are adapted to drop simultaneously into their associated groove and thereby, momentarily relieve the axial thrust on the holding member only when the cage and the bearing member are in a position to aline each pair of bearing elements with the groove occupying the same angular position as the pair of elements, and only one pair of bearing elements at a time registering with a groove in all other positions of the cage and bearing member whereby the remaining pairs of elements are effective to maintain a balanced axial thrust on the holding member.

4. A drill chip breaker comprising, in combination a rotatable drill holding member, bearing means for imparting an axial feeding thrust on said holding member, said bearing means including means rigid with the holding member providing an annular axially facing bearing track, a fixed bearing member providing on one face an annular bearing track in opposed relation to said first-mentioned bearing track, said bearing member having a series of relatively shallow drop grooves in said one face extending diametrically across the bearing track and spaced from each other at non-uniform arcuate intervals, a plurality of bearing elements interposed between said bearing tracks, and a bearing cage operative to retain said bearing elements spaced from each other at the same arcuate intervals as said grooves whereby the thrust on the driving member is momentarily relieved only when said bearing elements and said grooves are alined symmetrically, the spacing of said grooves and said bearing elements being such that in the passage of any pair of bearing elements over a groove other than the one which occupies the same angular position as that pair, the remainder of the bearing elements effectively engage the bearing tracks and maintain a balanced thrust on the holding member.

5. A drill chip breaker comprising, in combination, a casing, driving and driven members disposed coaxially in said casing and projecting at opposite ends thereof, said driven member being operative to support a, drill, cooperating means on said members connecting them for rotation as a unit and permitting relative axial movement therebetween, circumferential flanges formed on said members within the casing, an annular bearing member supported in said casing and extend-.

ing between said flanges, antifriction bearing elements interposed between the flange of the driving member and the adjacent face of the bearing member, other antifriction bearing elements interposed between the flange of the driven memberand the other face of said bearing member, said bearing member having a series of shallow grooves extending diametrically across its other face spaced apart at predetermined non-uniform intervals, a cage operative to retain said other bearing elements spaced apart similarly to the spacing of said grooves, said. bearing elements being operative to exert an axial thrust on the driven member at all times until the cage in its rotation reaches a position in which each pair of bearing elements is. alined with the groove oc cupylng the same angular position on the bearing member, the entry of said bearing elements into the grooves serving to relieve momentarily the holding member and then project it axially of the The following references are of record in the file of this patent:

UNITED STATES PATENTS Name I Date BullOCk Jan. 20, 1925 Number 

